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    <td bgcolor="#666699" width="10"><b><a href="http://irrlicht.sourceforge.net" target="_blank"><img src="../../media/irrlichtlogo.jpg" width="88" height="31" border="0"></a></b></td>
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        <div align="left"><b><font color="#FFFFFF">Tutorial 5.User Interface</font></b></div>
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        <p>This tutorial shows how to use the built in User Interface of the Irrlicht 
          Engine. It will give a brief overview and show how to create and use 
          windows, buttons, scroll bars, static texts and list boxes. </p>
        <p>The program which is described here will look like this:</p>
        <p align="center"><img src="../../media/005shot.jpg" width="259" height="204"><br>
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      <b><font color="#FFFFFF">Lets start!</font></b></td>
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    <td height="90" bgcolor="#eeeeff" valign="top"> <div align="left"> 
        <p>As always, we include the header files (conio and curses for getting 
          user input from the console), and use the irrlicht namespaces. We also 
          store a pointer to the Irrlicht device, a counter variable for changing 
          the creation position of a window, and a pointer to a listbox.</p>
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            <td> <pre>#include &lt;irrlicht.h&gt;
#include &lt;iostream&gt;<br>
using namespace irr;</pre> 
              <pre>using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;</pre>
              <pre>#pragma comment(lib, &quot;Irrlicht.lib&quot;)</pre>
              <pre>IrrlichtDevice *device = 0;
s32 cnt = 0;
IGUIListBox* listbox = 0;
</pre></td>
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        <p>The Event Receiver is not only capable of getting keyboard and mouse 
          input events, but also events of the graphical user interface (gui). 
          There are events for almost everything: Button click, Listbox selection 
          change, events that say that a element was hovered and so on. To be 
          able to react to some of these events, we create <br>
          an event receiver. We only react to gui events, and if it's such an 
          event, we get the id of the caller (the gui element which caused the 
          event) and get the pointer to the gui environment. </p>
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            <td> <pre>class MyEventReceiver : public IEventReceiver<br>{<br>public:<br>	virtual bool OnEvent(const SEvent&amp; event)<br>	{<br>		if (event.EventType == EET_GUI_EVENT)<br>		{<br>			s32 id = event.GUIEvent.Caller-&gt;getID();<br>			IGUIEnvironment* env = device-&gt;getGUIEnvironment();</pre>
              <pre>            switch(event.GUIEvent.EventType)
            {</pre>
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        <p> If a scrollbar changed its scroll position, and it is 'our' scrollbar 
          (the one with id 104), then we change the <br>
          transparency of all gui elements. This is a very easy task: There is 
          a skin object, in which all color settings are stored. We simply go 
          through all colors stored in the skin and change their alpha value. 
        </p>
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            <td height="80"> <pre>case EGET_SCROLL_BAR_CHANGED:<br>	if (id == 104)<br>	{<br>		s32 pos = ((IGUIScrollBar*)event.GUIEvent.Caller)-&gt;getPos();<br>					<br>		for (s32 i=0; i&lt;EGDC_COUNT ; ++i)<br>		{<br>			SColor col = env-&gt;getSkin()-&gt;getColor((EGUI_DEFAULT_COLOR)i);<br>			col.setAlpha(pos);<br>			env-&gt;getSkin()-&gt;setColor((EGUI_DEFAULT_COLOR)i, col);<br>		}<br>	}<br>break;</pre></td>
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        <p>If a button was clicked, it could be one of 'our' three buttons. If 
          it is the first, we shut down the engine.<br>
          If it is the second, we create a little window with some text on it. 
          We also add a string to the list box to log<br>
          what happened. And if it is the third button, we create a file open 
          dialog, and add also this as string to the list box.<br>
          That's all for the event receiver.</p>
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              <pre>       case EGET_BUTTON_CLICKED:
              if (id == 101)
              {
                 device-&gt;closeDevice();
                 return true;
              }</pre>
              <pre>              if (id == 102)
              {
                 listbox-&gt;addItem(L&quot;Window created&quot;);
                 cnt += 30;
                 if (cnt &gt; 200) 
                   cnt = 0;</pre>
              <pre>                 IGUIWindow* window = env-&gt;addWindow(
                       rect&lt;s32&gt;(100 + cnt, 100 + cnt, 300 + cnt, 200 + cnt), <br>                       false, // modal?
                       L&quot;Test window&quot;);</pre> 
              <pre>                 env-&gt;addStaticText(L&quot;Please close me&quot;, 
                       rect&lt;s32&gt;(35,35,140,50),
                       true, // border?,
                       false, // wordwrap?
                       window);

                 return true;
              }</pre>
              <pre>              if (id == 103)
              {
                 listbox-&gt;addItem(L&quot;File open&quot;);
                 env-&gt;addFileOpenDialog(L&quot;Please choose a file.&quot;);
                 return true;
              }</pre>
              <pre>              break;
          }
       }
       return false;
    }
 };</pre>
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        <p>Ok, now for the more interesting part. First, create the Irrlicht device. 
          As in some examples before, we ask the user which driver he wants to 
          use for this example:</p>
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          <td> <pre>int main()
{
  // ask user for driver
  video::E_DRIVER_TYPE driverType;


  printf(&quot;Please select the driver you want for this example:\n&quot;\<br>    &quot; (a) Direct3D 9.0c\n (b) Direct3D 8.1\n (c) OpenGL 1.5\n&quot;\<br>    &quot; (d) Software Renderer\n (e) Apfelbaum Software Renderer\n&quot;\<br>    &quot; (f) NullDevice\n (otherKey) exit\n\n&quot;);<br><br>  char i;<br>  std::cin &gt;&gt; i;<br>
  switch(i)<br>  {<br>    case 'a': driverType = video::EDT_DIRECT3D9;break;<br>    case 'b': driverType = video::EDT_DIRECT3D8;break;<br>    case 'c': driverType = video::EDT_OPENGL;   break;<br>    case 'd': driverType = video::EDT_SOFTWARE; break;<br>    case 'e': driverType = video::EDT_BURNINGSVIDEO;break;<br>    case 'f': driverType = video::EDT_NULL;     break;<br>    default: return 1;<br>  }	
  
  // create device and exit if creation failed
  device = createDevice(driverType, core::dimension2d&lt;s32&gt;(640, 480));<br>
  if (device == 0)
     return 1;
</pre> 
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      <p>The creation was successful, now we set the event receiver and store 
        pointers to the driver and to the gui environment. </p>
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          <td><pre>MyEventReceiver receiver;
device-&gt;setEventReceiver(&amp;receiver);
device-&gt;setWindowCaption(L&quot;Irrlicht Engine - User Inferface Demo&quot;);</pre>
            <pre>video::IVideoDriver* driver = device-&gt;getVideoDriver();
IGUIEnvironment* env = device-&gt;getGUIEnvironment();
</pre>
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      <p>We add three buttons. The first one closes the engine. The second creates 
        a window and the third opens a file open dialog. The third parameter is 
        the id of the button, with which we can easily identify the button in 
        the event receiver.</p>
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          <td><pre>env-&gt;addButton(rect&lt;s32&gt;(10,240,100,270), 0, 101, L&quot;Quit&quot;);<br>env-&gt;addButton(rect&lt;s32&gt;(10,280,100,320), 0, 102, L&quot;New Window&quot;);<br>env-&gt;addButton(rect&lt;s32&gt;(10,330,100,370), 0, 103, L&quot;File Open&quot;);</pre></td>
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      <p> Now, we add a static text and a scrollbar, which modifies the transparency 
        of all gui elements. We set the maximum value of the scrollbar to 255, 
        because that's the maximal value for a color value.<br>
        Then we create an other static text and a list box.</p>
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          <td><pre>env-&gt;addStaticText(L&quot;Transparent Control:&quot;, rect&lt;s32&gt;(150,20,350,40), true);<br>IGUIScrollBar* scrollbar = env-&gt;addScrollBar(true,
               rect&lt;s32&gt;(150, 45, 350, 60), 0, 104);<br>scrollbar-&gt;setMax(255);</pre>
            <pre>env-&gt;addStaticText(L&quot;Logging ListBox:&quot;, rect&lt;s32&gt;(50,110,250,130), true);
listbox = env-&gt;addListBox(rect&lt;s32&gt;(50, 140, 250, 210));</pre></td>
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      <br>
      To make the font a little bit nicer, we load an external font and set it 
      as new font in the skin. An at last, we create a nice Irrlicht Engine logo 
      in the top left corner. <br>
      <br>
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          <td> <pre>IGUISkin* skin = env-&gt;getSkin();<br>IGUIFont* font = env-&gt;getFont(&quot;../../media/fonthaettenschweiler.bmp&quot;);<br>if (font)<br>	skin-&gt;setFont(font);</pre>
            <pre>IGUIImage* img = env-&gt;addImage(<br>		driver-&gt;getTexture(&quot;../../media/irrlichtlogoalpha.tga&quot;),<br>		position2d&lt;int&gt;(10,10));</pre></td>
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      <p>That's all, we only have to draw everything.</p>
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            <pre>  while(device-&gt;run() &amp;&amp; driver)<br>  if (device-&gt;isWindowActive()) <br>  {<br>      driver-&gt;beginScene(true, true, SColor(0,122,65,171));
      env-&gt;drawAll();
      driver-&gt;endScene();
  }

  device-&gt;drop();</pre>
            <pre>  return 0;
}</pre>
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